Generally a double clutch transmission implies a transmission having two clutch devices therein. A double clutch transmission generally receives a torque input from an engine selectively at its two input shafts using two clutches, and it changes the torque and speed using gears on the two input shafts, and outputs them.
Such a double clutch transmission has been devised basically to compactly provide a multi-speed transmission having more than five speeds. The two clutches and synchronizing devices included in a double clutch transmission may be controlled by a controller, and accordingly, such a double clutch transmission may also realize an automated shift gear (ASG) that eliminates the necessity of manual shifting of a driver.
A clutch included in a double clutch transmission may be categorized as either a dry- or wet-type based on its operational scheme. A dry-type clutch utilizes the same principle as a clutch device conventionally disposed between an engine and a manual transmission. A wet-type clutch utilizes the same principle as a clutch device inside an automatic transmission.
A wet-type clutch generally has a higher torque capacity than a dry-type clutch. Therefore, for an engine of high output power, a wet-type clutch is appropriate. In order to stably transmit high output torque of a high powered engine, the widths of gears in the transmission should be large. Therefore, a double clutch transmission designed for a high torque engine may easily become very lengthy.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known in this country to a person of ordinary skill in the art.